Metformin is associated with survival benefit in pancreatic cancer patients with diabetes: a systematic review and meta-analysis.

Background: Pancreatic cancer is a highly lethal disease with a poor prognosis while metformin has been associated with a decreased risk of pancreatic cancer. Although the benefit of metformin was observed for pancreatic cancer prevention, it is not clear whether it can also affect the survival of pancreatic cancer patients with type 2 diabetes mellitus. A systematic review and meta-analysis was conducted to assess the effect of metformin on the survival of pancreatic cancer patients with type 2 diabetes mellitus.

[Femoral tunnel positioning in posterior cruciate ligament double-bundle reconstruction by computer aided design].

Objective: To study mechanical affect of knee joint of reasonable positioning of femoral tunnel during knee posterior cruciate ligament (PCL) double-bundle reconstruction and graft fixation after reconstruction by virtual reality interactive technology and evaluate the biomechanical response of knee after reconstruction by finite element analysis.

Methods: Knee specimens from five fresh frozen cadavers were used. Computer simulations and biomechanical experiments were used in this study.

Biomechanical comparison of osteoporotic distal radius fractures fixed by distal locking screws with different length.

Objectives: To evaluate the postoperative stability of osteoporotic distal radius fractures fixed with distal locking screws with different length.

Methods: A comminuted extra-articular dorsally unstable distal radius fracture, treated with volar locking plate system, was created. The 18 specimens were randomized into 3 groups based on distal locked screws with different length: Group A had unicortical screws with 50% length to the dorsal cortex.

Evaluation of biomechanical properties of anterior atlantoaxial transarticular locking plate system using three-dimensional finite element analysis.

Purpose: To evaluate a new anterior atlantoaxial transarticular locking plate system using finite element analysis.

Methods: Thin-section spiral computed tomography was performed from occiput to C2 region. A finite element model of an unstable atlantoaxial joint, treated with an anterior atlantoaxial transarticular locking plate system, was compared with the simple anterior atlantoaxial transarticular screw system.

Treatment planning of implants when 3 mandibular posterior teeth are missing: a 3-dimensional finite element analysis.

Purpose: To analyze the biomechanics of 3 designs of implant treatment for 3 teeth missing in posterior low arch quadrants.

Material And Methods: A posterior portion of the human mandible missing 44, 45, 46 and three 4.1 × 10 mm threaded ITI implants with crowns were used to construct the finite element model.

[Balloon inflating and cement filling for treatment of avascular necrosis of the femoral head: a three-dimensional infinite-element study].

Objective: To evaluate the biomechanical changes of balloon inflating and cement filling in avascular necrosis of the femoral head using finite-element analysis.

Methods: The procedure of percutaneous balloon inflating and cement filling was simulated in fresh specimen of human femoral head. CT scan and three-dimensional reconstruction were used to establish the three-dimensional model of the femoral head.

[Three-dimensional finite element analysis of biomechanical characteristics of cancellous screw in different bone densities].

Objective: To predict the cancellous screw stress distributions and pull-out strength in cancellous bone with different densities using 3-D finite element analysis and provide biomechanical evidence for screw implant in clinical practices.

Methods: Three-dimensional models of bones with low, medium and high bone density and a fixation screw were generated in Solidworks. Finite element analysis was performed after importing these models to Abaqus to simulate the pull- out process.

Differences of percutaneous retrograde screw fixation of anterior column acetabular fractures between male and female: a study of 164 virtual three-dimensional models.

Introduction: Percutaneous retrograde screw fixation of the anterior column has been recommended for the treatment of minimally displaced acetabular fractures. However, proper placement of the screw in anterior column is challenging because of its unique anatomy. There are few anatomic studies on this technique, and the differences between male and female have never been reported.

Application of computer-aided three-dimensional skull model with rapid prototyping technique in repair of zygomatico-orbito-maxillary complex fracture.

Background: With the advent of CAD/CAM and rapid prototyping (RP), a technical revolution in oral and maxillofacial trauma was promoted to benefit treatment, repair of maxillofacial fractures and reconstruction of maxillofacial defects.

Methods: For a patient with zygomatico-facial collapse deformity resulting from a zygomatico-orbito-maxillary complex (ZOMC) fracture, CT scan data were processed by using Mimics 10.0 for three-dimensional (3D) reconstruction.

[A finite element investigation of bilateral atlantoaxial trans-articular screws and atlas laminar hooks instrumentation].

Objectives: To investigate the mechanical properties of bilateral atlantoaxial trans-articular screws and atlas laminar hooks instrumentation with finite element method.

Methods: There was a volunteer with age of 28 years old, body height 172 cm, body weight of 60 kg and without cervical deformity by X rays. The ligamentous, nonlinear, three-dimensional finite element models of normal upper cervical spine (C0-3) was developed and validated.

[A three dimensional finite element study on stress distribution in maxillary central incisor restored with fiber post].

Objective: To study the stress changes of maxillary central incisor restored with or without fiber post using three dimensional finite element method, and analysis the role of fiber post in determining the stress distribution in dentin.

Methods: Three dimensional finite element models of maxillary central incisor with various remaining tooth structure were established by spiral CT, Mimics software and ANSYS software. Test samples were restored with all-ceramic crown and fiber post all-ceramic crown, respectively.

Biomechanical effect of vertebroplasty on the adjacent intervertebral levels using a three-dimensional finite element analysis.

Objective: To investigate the biomechanical effect of different volume, distribution and leakage to adjacent disc of bone cement on the adjacent vertebral body by three-dimensional osteoporosis finite element model of lumbar.

Methods: L(4)-L(5) motion segment data of the cadaver of an old man who had no abnormal findings on roentgenograms were obtained from computed tomography (CT) scans. Three-dimensional model of L(4)-L(5) was established with Mimics software, and finite element model of L(4)-L(5) functional spinal unit (FSU) was established by Ansys 7.

[Establishment of a testing system of three-dimensional spinal kinematics in vivo based on two- and three-dimensional image registration].

Objective: To investigate the feasibility of using two- and three-dimensional (2D/3D) image registration for establishing a testing system of 3D kinematics of the spine in vivo.

Methods: CT data of the adult human lumbar spine were collected and the two orthogonal images of the same specimen were captured using an X-ray fluoroscope at two different positions. The 3D computer models of L3 and L4 vertebrae were reconstructed.

[Biomechanical evaluation of nickel-titanium shape-memory alloy enclosed interlocking intramedular nail].

Objective: To study the biomechanical characteristics of Ni-Ti shape-memory alloy-enclosed interlocking intramedular nail Ni-Ti En for clinical application.

Methods: Six transverse fractures were induced in 6 fresh humeral shafts and fixed with Ni-Ti En, plate, interlocking intramedullary nail, and Ender nail, respectively. The specimens then underwent stress analysis for comparison of the bending strength, twisting force, and flexibility.

[Stress distribution on the femoral neck at different abduction angles of the hip joint: a finite element analysis].

Objective: To analyze the stress distribution and its changes of the femoral neck at different abduction angles of the hip joint to provide biomechanical evidence for the treatment of hip joint disease.

Methods: A three-dimensional finite element model of the femoral head region was reconstructed on the basis of data available in the dataset of No.1 Virtual Male Chinese.

[Comparative study of vertebral body stress distribution following insertion of artificial lumbar intervertebral disc].

Objective: To study vertebral body stress distribution of normal disc, post-Diskectomy and artificial disk respectively by 3-D finite element methods, and to explore artificial intervertebral disk insertion impact on stress distribution of vertebral body.

Methods: Models of normal disk, post-Diskectomy, artificial disk and L(4 - 5) motion segment were established by using finite element software MSC. MARK, then vertebral body stress was analyzed through model of L(4 - 5) motion segment respectively.

[The effect of disc degeneration on the structural property distributions in the cervical vertebral endplates].

Objective: To study the effect of disc degeneration on the structural property distributions in the cervical vertebral endplates.

Methods: A 2 mm-diameter hemispherical indenter was used to perform indentation tests at 0.03 mm/s to the depth of 2 mm at 20 normalized locations in 50 bony endplates of intact human cervical vertebrae (C2 approximately C7).

[3D image analysis of nasal orbit fossa through a laser scanner: a new method and application of 3D image].

Objective: This study was to introduce the method for obtaining accurate 3D data of soft tissues using a 3D scanner under non-contact condition and the standard 3D measurement of the nasal orbit fossa for plastic surgery.

Methods: A 3D laser scanner and the Geomagic software were used to obtain the standard facial contour of 30 Chinese people. The nasal orbit fossa, as the feature of beauty, was measured and the data were analyzed.

[Reconstruction of the mandibular model using a three-dimensional laser scanner].

Objective: To construct a three-dimensional (3D) mandibular model using a 3D laser scanner, and explore a new method for reconstructing the finite element geometry model.

Methods: A mandible specimen was scanned with the 3D laser scanner to form the point clouds of the mandibular surface, which were subsequently aligned for reconstruction of the mandibular model.

Result: A 3D model of the mandible surface was reconstructed, which could be used for finite element simulation.

[Biomechanical response of the femur-tibia model under impact loading of the body weight].

Objective: To study the biomechanical response and the role of articular surface on the femur-tibia model under impact loading of the body weight.

Methods: A three-dimensional finite element (FE) model of the femur-tibia composite was reconstructed using the image data of the knee joint of Virtual Chinese Human No.1 Male, and FE calculation was performed to simulate the impact of the body weight on the knee joint while walking.

[Establishment of Internet-based database of the Virtual Chinese Human dataset].

To establish an Internet-based database for the dataset of Virtual Chinese Human that is accessible to the interested researchers, modifications and compression of the original VCH-format dataset of Virtual Chinese Human were performed before it was uploaded to the server, and RAID0+1 storage technology was adopted with specific download accesses designed for different users. After dataset modification and compression, the data size was considerably reduced to allow convenient data storage and transfer. The RAID0+1 storage technology guarantees the security and high-speed download of data through different means established.

[Three-dimensional reconstruction of the knee joint of digitized Virtual Chinese Male No.1 by finite element simulation].

To provide a three-dimensional (3D) model of the knee joint of digitized Virtual Chinese Male No.1 for finite element simulation, the digitized image data of the serial sections of the virtual human knee joint were imported to a computer for 3D reconstruction using Mimics software after image segmentation and registration. Surface smoothing of the reconstructed model was performed with FreeForm system and transformation to IGES format executed.

Construction of dataset for Virtual Chinese Male No.1.

Objective: To establish digitized Virtual Chinese Human Male No.1 (VCH-M1) image dataset with a 0.2-mm equal interval.